Journal of Pest Science 78: 25-30, 2004

Influence of host plant species of Bemisia tabaci (Genn.) (Hom., Aleyrodidae) on some of the biological and ecological characteristics of the entomophagous Serangium parcesetosum Sicard (Col., Coccinellidae)

Abstract: The entomophagous, Serangium parcesetosum Sicard (Col., Coccinellidae) is an effective predator of some whitefly species. However, information on the influence of prey’s host plant species on its biological and ecological characteristics is still lacking in the literature. Therefore, the current study is focusing on the possible influence of three greenhouse and two field host plant species of Bemisia tabaci (Genn.) (Hom., Aleyrodidae) on the number of eggs laid by S. parcesetosum. In addition, because of the economic importance and wide spread of cucumber in greenhouse and cotton in field, they were selected to investigate further the development, mortality, longevity and reproduction of S. parcesetosum at a high temperature in the laboratory. Results showed that S. parcesetosum was able to lay eggs on all the five host plant species of B. tabaci, whether these are greenhouse or field plants. However, S. parcesetosum females laid significantly the highest number of eggs on cucumber among the three-greenhouse plant species used, followed by tomato and then sweet pepper. In contrast, from the two-field plant species, significantly higher number of eggs was laid on tobacco rather than on cotton. S. parcesetosum could develop either on cucumber or on cotton as preferable host plant species for B. tabaci. There were significant differences in mean developmental duration of larval instars between both host plant species within the same sex, in which it was significantly shorter on cucumber than on cotton. Mean total developmental duration from egg to adult emergence indicated no significant differences between both host plant species within the same sex, where it valued a mean of 15.9 (♀♀) and 15.1 (♂♂) days on cucumber, while on cotton it was a mean of 17.2 (♀♀) and 16.2 (♂♂) days. Total mortality percentage of S. parcesetosum during development from egg to adult stage was lower on cucumber than on cotton, in which it valued 20.6% and 23.8% on both host plant species, respectively. Longevity of S. parcesetosum varied according to host plant species and sex, and it lasted a mean of 63.4 (♀♀) and 50.3 (♂♂) days on cucumber, while on cotton it valued 92.4 (♀♀) and 52.5 (♂♂) days. On cucumber, mean period of oviposition of S. parcesetosum was significantly longer than on cotton. Mean total fecundity was significantly higher on cucumber than on cotton, where it was 97.7 and 31.0 eggs/♀ on both plants, respectively.